Midsection and Cowl Assembly for an Outboard Marine Drive

The present invention relates to outboard marine drives, and more particularly to a new midsection housing and cowl assembly for enclosing the midsection housing of an outboard marine drive.

An outboard marine drive generally includes an upper engine portion and a lower gear case. Typically, the two portions are joined by a driveshaft housing which includes a driveshaft, an exhaust passage, supply and return cooling water passages, and in some engine configurations, an integral oil sump. Other configurations requiring an oil sump have a separate reservoir mounted on the outboard drive.

There are several drawbacks to this configuration including producing excessive noise from the exhaust system, exposing the operator of the outboard drive to the hot oil sump cavity, allowing the hot oil sump cavity to be susceptible to contact with the cool water where the marine drive operates. Such exposure prevents maintaining consistent oil temperature and, in the case of operating in salt water, causes the water to evaporate leaving an unsightly salt residue which builds up and is difficult to remove. Further, an exposed die-cast driveshaft housing requires special sanding and preparation to produce a customer acceptable finish.

The present invention includes a new midsection housing and a 2-piece cowl assembly enclosing the midsection housing which overcome the above stated disadvantages of prior configurations. In one embodiment, the midsection housing incorporates an integrated oil sump for a four-cycle engine which is covered and isolated from outside contact by the two-piece cowl assembly and further, eliminates the need to have a separate oil sump reservoir.

One object of the invention is to provide a cowl assembly which provides isolation of the oil sump located within the midsection housing to prevent external contact with the hot oil sump and to maintain the oil temperature by isolating the oil sump from the splashing of external water in which the outboard drive operates.

Another object of the present invention is to provide a cowl assembly for muffling the noise of the engine exhaust traveling through the midsection housing of an outboard marine drive.

Yet another object of the invention is to provide a new midsection housing which encircles the exhaust passage in engine fluids for further muffling the noise of the engine exhaust traveling through the midsection housing.

A further object of the invention is to eliminate the expense involved in hand-sanding the die-cast driveshaft housing to provide a customer acceptable finish on the unattractive die-cast structure by using molded plastic cowl sections, which accept a paint finish directly out of the mold, for covering the die-cast midsection housing.

Yet another object is to provide a midsection housing and cowl assembly which permits an operator to easily drain engine oil completely and cleanly without removing the outboard drive from the boat and without having to remove the boat from the water. Further, the operator may drain the oil while remaining in the boat and need not enter the water.

Another object of the invention provides a simple and effective joint for easy assembly of the two cowl sections and maintaining the cowl sections in alignment.

FIG. 1 is a side elevation view of an outboard marine drive.

FIG. 2 is an exploded perspective view of a portion of the structure of FIG. 1.

FIG. 3 is an exploded perspective view of a portion of the structure of FIG. 2.

FIG. 4 is an enlarged partial sectional view of a portion of the structure of FIG. 1.

FIG. 5 is a sectional view taken along line 5--5 of FIG. 4.

FIG. 6 is an enlarged sectional view taken along line 6--6 of FIG. 5.

FIG. 7 is a rotated view of the structure of FIG. 1.

FIG. 8 is an exploded perspective view of a portion of the structure of another embodiment of FIG. 1.

FIG. 9 is an exploded perspective view of a portion of the structure of FIG. 8.

As shown in FIG. 1 and in accordance with the present invention, an outboard marine drive 10 includes an upper power head 12, a lower gear case 14, and a midsection 16 which extends from power head 12 to gear case 14. A propeller 18 is provided at the aft end of gear case 14 for propelling a boat through water, as is well known. Water inlet openings 15 are provided in gear case 14 to supply cooling water to power head 12. The upper power head 12 includes an upper cowl assembly 20 with a bottom sealing edge 21, and midsection 16 includes a midsection cowl assembly 22 with a top sealing edge 23. Outboard drive 10 is mounted to a boat (not shown) about a mounting axis 24 and is rotatable about a steering axis 26, as is all well known.

Referring to FIG. 2, midsection 16 of FIG. 1, is further defined to include midsection housing 28 and adapter plate 30. Adapter plate 30 adapts the midsection housing 28 to power head 12, FIG. 1. The midsection cowl assembly 22 of FIG. 1, includes starboard cowl section 32 and port cowl section 34 which enclose midsection housing 28 and adapter plate 30 when assembled together. Cowl sections 32 and 34 have U-shaped sealing channels 36 and 38, respectively, which extend around the inside perimeter of each cowl section 32 and 34 such that when assembled, U-shaped channels 36 and 38 encircle compressible seal 40 which wraps sealing edge 42 of adapter plate 30. Cowl sections 32 and 34 are held together about midsection housing 28 and adapter plate 30 with fastening bolts 44 which extend through holes 46 of the starboard cowl section 32 and into the threaded bosses 48 of port cowl section 34. Tightening fastening bolts 44 into threaded bosses 48 draws channels 36 and 38 over compressible seal 40 and sealing edge 42 of adapter plate 30 to provide water resistant sealing in the area above adapter plate 30. Starboard cowl section 32 has edge portion 50 including tongue portion 52, FIG. 6. Port cowl section 34, FIG. 2, has edge portion 54 including grooved section 56, FIG. 6. Edge portions 50 and 54, FIGS. 2 and 6, cooperate to form a tongue and groove joint which eases installation and maintains the cowl sections in alignment.

Cowl sections 32 and 34, FIG. 2, have top edge portions 58 and 60, respectively, to form top sealing edge 23, FIG. 1, of midsection cowl assembly 22. Top sealing edge 23 of cowl assembly 22 cooperates with bottom sealing edge 21 of upper cowl assembly 20 to form a water resistant joint between upper cowl assembly 20 and midsection cowl assembly 22 with a compressible seal (not shown) therebetween, similar to that described in U.S. Pat. No. 4,875,883, incorporated herein by reference.

Starboard cowl section 32, FIG. 2, has opening 62 to receive fuel line connector seal 64. Fuel line connector 66 fits within hole 68 of seal 64 and is supported by bolt 70 extending through passage 72 of fuel line connector 66 and through passage 74 of cowl section 32. Bolt 70 is threaded into boss 76 of cowl section 34. Passage 78 of fuel line connector seal 64 is provided to accommodate either an electrical harness (not shown) on electronically controlled outboard drives, or for cables (not shown) on mechanically controlled outboard drives.

Lever latch 80, FIG. 2, is pivotally connected to starboard cowl section 32 by pin 88 extending through passage 82. Bushings 84 and 86 fit over pin 88 of lever latch 80 and fit into passage 82. Washer 90 and catch 92 are connected to pin 88 of lever latch 80 with fastener 94. When cowl sections 32 and 34 are assembled about midsection housing 28, and upper cowl assembly 20, FIG. 1, is in place over midsection cowl assembly 22, and latch lever 80 is in its horizontal position as shown in FIG. 2, catch 92 at engagement surface 93 engages a stationary pin (not shown) of the upper cowl assembly 20, and exerts sealing pressure compressing a sealing gasket (not shown), positioned between bottom sealing edge 21 of cowl assembly 20 and top sealing edge 23 of cowl assembly 22. This type of latching and sealing arrangement is known in the prior art, for example U.S. Pat. No. 4,800,854, incorporated herein by reference. The latch is released by rotating lever latch 80 counterclockwise, as viewed in FIG. 2, to a vertical position, such that catch 92 rotates counterclockwise, and engagement surface 93 disengages the stationary pin of upper cowl assembly 20.

Engine exhaust created by an internal combustion engine as the power head 12, FIG. 1, is channeled through passage 96, FIG. 2, of adapter plate 30 from power head 12, FIG. 1. Engine exhaust is then channeled downwardly through passage 98, FIGS. 2-4, of midsection housing 28. Exhaust pipe 102, FIG. 3, fits into the bottom portion of passage 98 to transfer engine exhaust to the lower gear case 14, FIG. 1, where it is discharged through propeller 18, as is commonly known. However, during idle conditions, the water pressure about submerged propeller 18 creates excessive exhaust back pressure through exhaust pipe 102 and passage 98, FIG. 4. To provide a less restrictive path during idle conditions, exhaust relief passage 104, FIG. 4, is provided in adapter plate 30 as is well known and further described in U.S. Pat. No. 4,668,199 incorporated herein by reference. Exhaust relief boot 106, FIGS. 2 and 4, is press fit into relief passage 104 of adapter plate 30 and is provided to extend exhaust relief passage 104 through cowl assembly 22 at opening 107, FIG. 2. Semicircular opening 107, FIG. 2, in port cowl section 34 and a corresponding semi-circular opening in starboard cowl section 32 (not shown) provide an exterior passage for the exhaust relief boot 106 in assembled midsection cowl assembly 22, FIG. 1.

Midsection housing 28, FIG. 2, includes lower splashguard 108 extending horizontally, laterally and outwardly therefrom. Splashguard 108 blocks or restricts upward water flow into midsection cowl assembly 22, FIG. 1, when outboard drive 10 travels through a body of water. Driveshaft 110, FIG. 4, is forward of midsection housing 28 and passes through midsection housing 28 at passages 112 and 114, FIGS. 2 and 3, and through adapter plate 30 at passage 116, FIG. 2. Driveshaft 110, FIG. 4, is enclosed by midsection cowl assembly 22 creating driveshaft pocket 111. Driveshaft seal 118, FIGS. 2 and 4, prevents water from entering power head 12, FIG. 1. Upper shift shaft 120, FIG. 4, passes through midsection cowl assembly 22 through seal 122, and extends downwardly connecting lower shift shaft 121 at connector 123 and into gear case 14, FIG. 1, through outboard drive mounting passage 124, FIGS. 2-5. Cowl sections 32 and, 34, FIG. 2, have corresponding outboard drive mount openings 126 and 128, respectively, to accommodate the insertion of the swingable arm of a transom bracket into mounting passage 124 for attaching outboard drive 10 to the transom of a boat similar to that shown in U.S. Pat. No. 4,932,909, incorporated herein by reference.

Water pump cavity 130, FIG. 4, provides a water reservoir wherein water pump 132 is submerged which assures that water pump 132 is primed with water to provide consistent pumping. Water passage 134 connects discharge water cavity 136 and water pump cavity 130, and overflow drain hole 138 maintains the water level in water pump cavity 130 above water pump 132. Water pump 132 is driven by driveshaft 110 and draws cooling water from gear case 14, FIG. 1, through water inlet openings 15 and pumps cooling water vertically through supply tube 140, FIGS. 34, to power head 12, FIG. 1, as is all well known, for example U.S. Pat. No. 4,940,402, incorporated herein by reference. Water supply tube 140, FIGS. 3-4, is supported by bracket 142 and connected to water pump 132, FIG. 4, with water pump seal 144. Water supply tube seal 146, FIGS. 2-3, provides sealing between water supply tube 140 and adapter plate 30, FIG. 2.

Cooling water is circulated through power head 2, FIG. 1, and discharged through passages 148 and 150, FIGS. 2-5, filling discharge water cavity 136, FIG. 4, in midsection 28 to water level 152 corresponding to inlet 154 of stand pipe 156, thereby partially submerging exhaust pipe 102 in discharged coolant. Overflow drain hole 138, FIG. 4, in water pump cavity 130 and water passage 134 are sized small enough that water level 152 in discharge water cavity 136 is unaffected because of the much greater amounts of discharge water entering cavity 136 from power head 12. Stand pipe 156, FIGS. 3-4, provides a path to discharge cooling water through lower gear case 14, FIG. 1. Fluted end 158, FIGS. 3-4, of stand pipe 156, is inserted into cavity 136, FIG. 4, and is sized such that water level 52 is slightly above the bottom of oil sump 160. Stand pipe 156 and exhaust pipe 102 are held in place by retainer 62, FIGS. 3-4.

In four-cycle engine applications, oil sump 160, FIGS. 2-5, is formed by a hollowed upper half of midsection housing 28 and encircles discharge water cavity 136 and exhaust pipe 102 above water line 152. In this manner, exhaust pipe 102 is encircled by discharged coolant and oil thereby muffling the noise created by the engine exhaust traveling through exhaust pipe 102 to provide quieter operation. Oil dipstick 164, FIG. 2, and oil dipstick tube 166 enter oil sump 160 through passage 168 of adapter plate 30. Oil pickup 170, FIGS. 2-5, is submerged within oil sump 160 to withdraw oil from oil sump 160 for engine lubrication, as is well known. Oil pressure relief valve 172, FIG. 3, piston 174 and pressure relief spring 176 are assembled with retaining cotter pin 178 and mounted to adapter plate 30, FIG. 2, and positioned over oil sump 160, FIG. 3, to relieve excess oil pressure as is commonly known. Cowl sections 32 and 34, FIG. 2, forming midsection cowl assembly 22, FIG. 1, isolate oil sump 160 from both external contact, and from the cool water wherein the outboard drive 10, FIG. 1, is operated.

Threaded oil drain plug 180, FIG. 3, engages a threaded drain hole in a housing boss (not shown) similar to boss 182 in midsection housing 28. Boss 182 is provided to allow future adaptation of an alternative oil drain arrangement. Gasket 184 provides sealing between oil drain plug 180 and the housing boss drain hole. Donut shaped rubber dampers 183 and 185, FIG. 2, are placed between cowl sections 32 and 34, respectively, and midsection housing 28 to provide shock absorption and dampening for the lower ends of cowl sections 32 and 34. Rubber damper 183 is placed over boss 182 of midsection housing 28 and rubber damper 185 is placed over drain plug 180 and the corresponding housing boss (not shown). Cowl oil drain access 86, FIG. 2, in cowl section 34 provides external access to drain plug 180, FIG. 3, without disassembling cowl assembly 22, FIG. 1. This arrangement and position of oil drain plug 180, FIG. 3, allows an operator to drain engine oil completely without removing the outboard drive 10, FIG. 1, from the boat (not shown), by tilting outboard drive 10 about horizontal mounting axis 24 such that power head 12 is positioned over the boat, and gear case 14 is out of the water. As shown in FIG. 7, this position results in outboard drive 10 being tilted to an angle slightly less than 90.degree.. Outboard drive 10 may then be turned about steering axis 26 to the full port side position, as shown by arrow 188, such that oil drain plug 180 and cowl oil drain access 186 face downwardly, and directly above, water line 190. While in this position, removing oil drain plug 180 permits engine oil to drain vertically without running down the side of the outboard drive 10. This arrangement and position allows an operator to drain engine oil directly into an oil drain pan (not shown) while remaining in the boat, without removing the outboard drive from the boat, and without spilling engine oil into the water. To further avoid spilling oil in the water, it is preferred that the oil drain pan be designed to float.

FIG. 8 is similar to FIG. 2 and shows an alternative embodiment. Midsection housing 28' has an alternate mounting passage 124' and a corresponding lower driveshaft passage 112'. Midsection housing 28' also has an idle relief chamber 200 and corresponding flange 202 to accommodate alternate adapter plate 30' and gasket 204. Cowl sections 32' and 34' have enlarged openings 107' to accommodate boot 206 which has an exhaust relief passage 208 and a telltale water passage 210 to indicate the proper functioning of water pump 132, FIG. 4.

FIG. 9 shows alternate midsection 28' having a modified oil pickup 170' and a modified water supply tube 140' to accommodate the alternate adapter plate 30', FIG. 8. FIG. 9 also shows unified exhaust pipe 102', standpipe 156', and retainer 162' as assembly 212 to ease installation.

As is evident from the embodiments shown, other various equivalents, alternatives, and modifications are possible and within the scope of the appended claims. It is recognized that the cowl sections of the current invention, may be made adaptable to existing marine drives.